236 HARVARD LAW REVIEW Three dissenting justices, however, argued that the property itself was an agency of the United States, and was therefore as immune from state taxation as are the bonds of the United States or the operations of the United States Bank. Less than three months later, in The Delaware Railroad Tax,^ Mr. Justice Field indicated without objection from any of his colleagues that a state tax on the property of an interstate carrier was not a regulation of inter- state commerce. From that day forward it has never been seriously doubted that a tax on tangible property used as an instrument of interstate commerce is not a tax on that commerce.' Such disputes as we have here to chronicle relate to the propriety of methods adopted for assessing that property. Mr. Justice Field's remarks about property taxation in The Delaware Railroad Tax ^° must be regarded as obiter, since he had previously stated that the tax before the court was not a tax on property, but one "upon the corporation itself, measured by a percentage upon the cash value of a certain proportional part of the shares of its capital stock." " It is to be inferred that the tax, if one on property, would have been held to be faulty because of the method by which the amount of property in Delaware was determined. The statute required each company subject to the act to pay a tax of one-fourth of one per cent on such proportion of the cash value of all its shares as the length of the line in Dela- ware bore to the total mileage. It was conceded that the "ratio of the value of the property in Delaware to the value of the whole property of the company" was considerably "less than that which the length of the road in Delaware bears to its entire length." *^ From this Mr. Justice Field concluded that "a tax imposed upon the property in Delaware according to the ratio of the length of its road to the length of the whole road must necessarily fall on property without the State,"" and observed that, upon the assump- » 18 WaU. (U. S.) 206 (1873). • In 1891 Mr. Justice Gray on page 23 of his opinion in the Pullman case, note 33, infra, declared: "It is equally well settled that there is nothing in the Constitution or laws of the United States which prevents a State from taxing personal property, employed in interstate or foreign commerce, like other personal property within its jurisdiction." 1" Note 8, supra. " 18 Wall. (U. S.) 206, 231 (1873). « Ibid., 230. " Ibid., 231.
